genirq: check chip->ack before calling
Impact: fix theoretical NULL dereference
The generic irq layer doesn't know whether irq_chip has ack routine on some
architectures or not. Upon that, before calling chip->ack, we should check
that it's not NULL.
Signed-off-by: Wang Chen <wangchen@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c
index 6eb3c79..0ad02d7 100644
--- a/kernel/irq/chip.c
+++ b/kernel/irq/chip.c
@@ -290,7 +290,8 @@
desc->chip->mask_ack(irq);
else {
desc->chip->mask(irq);
- desc->chip->ack(irq);
+ if (desc->chip->ack)
+ desc->chip->ack(irq);
}
}
@@ -475,7 +476,8 @@
kstat_incr_irqs_this_cpu(irq, desc);
/* Start handling the irq */
- desc->chip->ack(irq);
+ if (desc->chip->ack)
+ desc->chip->ack(irq);
desc = irq_remap_to_desc(irq, desc);
/* Mark the IRQ currently in progress.*/